On-cell battery fuel gauges may require a user to press two buttons, wait several seconds, and then observe an indication of the state of charge of the battery. Such a solution may require removing the batteries from the device and checking the battery to decide whether it is necessary to replace the battery. As such, solutions that avoid removal of a battery from a device to check the remaining capacity provide significant advantages for consumers.
In some embodiments, a battery status may be detected by remote indication using an analog to digital converter (ADC) and a Near Field Communication (NFC) Integrated Circuit (IC) together with a magnetic diverter and a thin foil antenna on the battery label. Application software, for example executing on a smart phone, may be used to receive battery status information remotely. Such battery status information may include the battery voltage that is then used to provide an indication of battery status to the user.
Conventionally packaged silicon integrated circuits together with the associated discrete resistors and capacitors when installed, for example, directly onto the label of the battery cell may increase the diameter of the cell beyond the capabilities of many existing device cavities. Furthermore, NFC detection range may in some embodiments be limited to several centimeters.
Operation of RF transceivers near metal surfaces may present technical challenges, for example with parasitic coupling of the antenna to the metal surfaces. In some embodiments battery cells may be constructed with a conductive metal can, for example constructed with steel, particularly primary alkaline batteries available to consumers. The presence of such metal surfaces near an antenna installed on a wireless transmitter circuit may detune the antenna significantly, deteriorating performance and reducing the usable range to a receiving device.